Safety device employing meltable tube socket



4, 1965 w. L. ARRINGTON 3,202,882

SAFETY DEVICE EMPLOYING MELTABLE TUBE SOCKET Filed Feb. 21, 1965 f mz.

William L. Arringfon M/ BY such as a short circuit or the like.

United States Patent 3,202,332 SAFETY DEVICE EMPLOYING MELTABLE TUBE SOCKET William L. Arrington, Roselle, 111., assignor to Admiral Corporation, Chicago, *Ill., a corporation of Delaware Filed Feb. 21, 1963, Ser. No. 260,223

7 Claims. (Cl. 317120) This invention relates in general to safety devices'and more particularly it relates tov safety devices for use in television receivers.

' As is well known in the art, the high voltage transformer and its associated high voltage rectifier tube are potential shock hazards and they are, therefore, generally enclosed within an enclosure which is usually referred to as the high voltage cage. In the large console type television receivers, the high voltage transformer and the high voltage rectifier tube are generally mounted side by side in the high voltage cage. In the smaller, luggage-type portable television receivers, however, the available space is limited and the present practice has been to mount the tube socket for the high voltage rectifier tube on top of the high voltage cage in a manner such that the rectifier tube extends downwardly inside of the high voltage cage directly over the high voltage transformer. In both cases, the high voltage cage is usually vented to create a chimney-like arrangement to dissipate the heat which is generated by these components.

When the tube socket is mounted on top of the high voltage cage, itis desirable'to provide some means to circumvent the potential fire hazard created should the insulating material between the windings on the high voltage transformer be set on fire due to a malfunction, The resulting fire generates sufficient heat to melt the tube socket and, eventually, the tube socket and tube both drop into the high voltage cage, leaving the top of the high voltage cage open. The chimney effect carries the fire out of the top of the high voltage cage, the consequence of which is obvious.

' The tube sockets presently used for high voltage rectifier tubes are fairly standard in the television industry, and are generally fabricated of a non-flammable polyethylene type material. While these tube sockets have excellent electrical characteristics and are non-flammable, they suffer from the disadvantage of being meltable. Various attempts have been made to fabricate a com parable tube socket capable of withstanding the intense heat which is generated when the high voltage transformer burns, but fabrication costs have been prohibitive, particularly where the intended use of the tube socket is in a highly competitive item such as a television receiver. Accordingly, it is the principal object of this invention to provide an inexpensive safety device foreliminating this potential fire hazard.

It is a further object of this invention to modify the presently used type of high voltage cage with an inexpensive safety device which functions in conjunction with the components therein to eliminate the fire hazard presented thereby.

in accordance with the principal object of this invention, a simple, inexpensive platform of a non-combustible, nonconductive material is mounted inside the high voltage cage immediately below the tube socket. The platform has an aperture smaller'than the circular base of the tube socket through which air normally flows from the bottom to the top of the high voltage cage. With this arrangement, when a fire of sufiicient'intensity to melt the tube socket occurs within the high voltage cage, the tube socket sags onto, and is supported by, the platform and, since the aperture in the platform is smaller than 3,202,882 Patented Aug. 24, 1965 the circular base of the tube socket, the aperture is sealed. This action, in essence, closes the draft for the chimney and the fire is effectively retarded and, in most cases, extinguished. In any event, the fire or flame is contained within the high voltage cage.

Other objects of this invention will be readily apparent from a reading of the following specification taken in conjunction with the drawing, in which:

FIG. 1 is a front view of a high voltage cage including the safety device of this invention,

FIG. 2 is a top view of the high voltage cage shown in FIG. 1, and

FIG. 3 is a top view of the safety device.

Referring now to the drawing, high voltage cage 1 is shown as a rectangular box having a back wall 12, a top wall 13, and two side walls 14 and 16. A cover 17 forms the front wall for high voltage cage 10 and is removably attached to extending tabs 19 and 21. An aperture 15 is formed in top wall 13 for receiving circular body portion 18 of tube socket 26 which extends inside of high voltage cage 10. Aperture 15 is made larger than circular body portion 13 in order to provide air spaces 11. Side walls 14 and 16 each have a plurality of air vents (not shown) along the lower edges thereof. These air vents and air spaces 11 in top wall 13 form a chimney-like arrangement to allow air to flow through high voltage cage 10 for dissipating the heat generated by high voltage transformer 34 and high voltage rectifier tube 26. 1

Tube socket 29, mounted on top of high voltage cage It by means of a pair of flanges or the like 22, is of the non-larnmable polyethylene type well known in the art. The circular body portion 18 includes connector pins for retaining the high voltage rectifier tube 26 and for making electrical connections to the elements thereof. A polyethylene cap 24 fits over body portion 13 of tube socket 26 (as shown in FIG. 1) to prevent accidental contact from being made with connector pins 25. As previously stated, tube sockets of this type have excellent electrical characteristics and are non-combustile but have the undesirable characteristic of being meltable.

High voltage transformer 34 has a number of different windings (not shown) providing different electrical potentials to various circuits within the television receiver. It is mounted by means of a pair of screws or the like 3 on back wall 12 of high voltage cage 10. Each of these windings are separated from one another by means of insulating material (not shown), such as paper and wax. An insulating board electrically insulates high voltage transformer 34 from high voltage cage 10. Back wall 12 of high voltage cage 10 also has an aperture (not shown) formed therein for allowing a plurality of connector pins 27 which are secured to insulating board 35 to pass through back wall 12 without making electrical contact with high voltage cage 10. The high voltage transformer windings are connected to connector pins 27 and external connections are, in turn,.made to the windings by connecting conductor leads to connector pins 27. Conductor lead 32 and polyethylene connector cap 31) connect plate cap electrode 28 of high voltage rectifier tube 26 to one terminal of one of the windings on high voltage transformer 34. A conductor lead 31 is looped about core of high voltage transformer 34 and connected to a pair of connector pins of tube socket 2%.

A platform 42 fabricated of a non-combustible, non conductive material is mounted inside high voltage cage 19 by means of tabs or the like 45, which may be stamped and bent out of side walls 14 and 16 to form a ledge on which the edges of platform 42 rest. Platform 42 has an aperture 44 which is larger than the base of high 1 J voltage rectifier tube 26, thus enabling tube 26 to be easily passed therethrough and mounted in tube socket 2t). Aperture 44 is smaller than the circular base portion of tube socket 20, for reasons to be explained; Platform 42 is mounted approximately one-eighth /8) of an inch below the circular base portion of tube socket 20 primarily to. allow air to flow through aperture 44 from the bottom to the top of high voltage cage 16. Mounting platform 42 in this manner also provides a tolerance for inserting platforms when the tabs or the like 45 are inaccurately stamped or the platforms are warped. Each of the corners of platform 42 is beveled to provide additional air spaces for air to flow through to the top of high voltage cage 10.

With this arrangement, air normally flows through the air vents in sidewalls 14 and 16, aperture 44 and the beveled-corners of platform 42 and out of air spaces 11 about tube socket 20 in top wall 13. When a fire of sufficient intensity to melt tube socket 20 occurs within high voltage cage 10, tube socket 20 sags onto, and is supported by, platform 42 and, since aperture 44 is smaller than the base of tube socket 2t), aperture 44 is sealed. It may be noted that by mounting high voltage rectifier tube 26 in a downwardly extending position in high voltage cage 10, the weight of tube 26 exerts a downward vertical force and causes tube socket 20 to sag substantially uniformly and aperture 44 in platform 42 is therefore rapidly sealed. This action, in essence, partly closes the draft for the above-described chimneylike arrangement and the fire is retarded and, in most cases, extinguished. If it is not extinguished, the heat causes tube socket 20 to continue to melt and, eventually, because of the action of flanges 22 which are used to mount tube socket 20 in aperture 15 in top wall 13, tube socket 20 sags and spreads out sealing the air spaces 11 about tube socket 20 in top wall 13 Whenthis' occurs, the drafe is completely closed and the air flow is stopped. The fire, in all cases, is retained within high voltage cage and eventually extinguished, hence eliminating the fire hazard.

What has been shown and described is a simple, inexpensive safety device for eliminating the potential fire hazard created by the burning of the high voltage transformer in a television receiver. It is of course obvious that numerous modifications of the safety device and the high voltage cage, as shown and described, may be made without departing from the scope of the invention. For example, to mention just one of the possible modifications which may be made, the aperture in the top wall of the high voltage cage could be made the size of the tube socket so that the tube socket would fit tightly in the aperture. The top wall would then be perforated and the corners of the platform would not be beveled, as shown. With this arrangement, air flow would be prevented when the tube socket sags onto the platform and seals the aperture therein.

j The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a television receiver, a high voltage cage having an aperture in the top wall thereof; a burnable trans- .former in said high voltage cage; a tube socket fabricated of a meltable, non-flammable material mounted in said aperture; a platform of non-flammable, non-meltable material; an aperture in said platform for allowing air to circulate through said high voltage cage; said platform mounted in said high voltage cage in a position intermediate said transformer and said tube socket such that said tube socket in melting sags into said high voltage cage and seals said aperture in said platfrom thereby preventing said air from circulating in said high voltage cage, whereby fire resulting from the burning of said transformer is retarded and prevented from escaping from said high voltage cage. 7

2. In a television receiver, a high voltage cage having an aperture in the top wall thereof; a burnable transformer in said high voltage cage; a tube socket fabricated of a meltable, non-flammable material mounted in said aperture; a platform of non-flammable, non-meltable material; an aperture in said platform for allowing air to circulate through said high voltage cage; said platform mounted in said high voltage cage between said tube and extended through said aperture in said platform, the weight of said vacuum; tube causing saidtube socket to sag more uniformly, whereby fire resulting from the burning of said transformer is quickly retarded and prevented from escaping from said high voltage cage.

3. In a television receiver, a high voltage cage hav:- ing an aperture in the top wall thereof; a burnable transformer in said high voltage cage; a tube socket fabricated of a meltable, non-flammable material mounted in said aperture in said top wall, said tube socket having a body portion smaller than said aperture in said topwall and a pair of flanges extending from said body portion for mounting said tube socket in said aperture; an aperture in at least one other Wall of said high voltage cage for permitting air to flow through said high voltage cage and out of the air spaces between said tube socket and said aperture in said top wall; a platform of non-flammable, non-meltable material having an aperture therein, said platform mounted in said high voltage cage, between said tube socket and said transformer such that said air flows through said aperture in said platform and such that said tube socket in melting sags into said high voltage cage into retaining relationship with said platform and seals said aperture in said platform thereby preventing said air from flowing, whereby fire resulting from the burning of said transformer is retarded and prevented fromescaping from said high voltage cage.

- .4. In a television receiver, the combination as claimed in claim 3, wherein said platform is beveled on its corners to allow said air to flow more freely, and wherein said tube socket in being retained by said platform melts and seals said air spaces between said tube socket and said aperture in said top wallthereby preventing said air from flowing through. said beveled corners to said air spaces.

, 5. In a television receiver, a high voltage cage having an aperture in the top wall thereof; a platform of nonfiammable, non-meltable material mounted in said high voltage cage dividing said high voltagecage'into first and second compartments, said'first compartment being physically below said second compartment; a burnable transformer-in said first compartment; a tube. socket fabricated of a meltable, non-flammable material mounted in said aperture and extending into said second compart- -ment; an aperture in said platform for permitting air to flow therethrough from said first compartment to said second compartment, said tube socket in melting sagging into said high voltage cage and sealing said aperture in said platform thereby preventing said air flow into said second compartment, whereby fire resultingfrom the burning ofsaid transformer is retarded and prevented from escaping from said high voltage cage.

6. In a television receiver, a high voltage cage having an aperture in the top wall thereof; a platform of non-flammable, non-meltable material mounted in said high voltage cage dividing said high voltage cage into first and second compartments, said first compartment being physically'below said second compartment; a burnable transformer in said first compartment; a tube socket fabricated of a meltable, non-flammable material mounted insaid aperture and extending into said second compartment; an aperture in said platform for permitting air to flow therethrough from said first compartment to said second compartment, said tube socket in melting sagging into said high voltage cage and sealing said aperture in said platform thereby preventing said air fiow into said second compartment, and a vacuum tube disposed in said tube socket and extended downwardly through said aperture in said platform into said first compartment, the weight of said vacuum tube causing said tube socket to sag more uniformly, whereby fire resulting from the burning of said transformer is quickly retarded and prevented from escaping from said high voltage cage.

7. In a television receiver, a high voltage cage having an aperture in the top Wall thereof; a high voltage socket fabricated of meltable, non-flammable material mounted in said aperture in an inverted position whereby a portion of said socket is inside the cage and at least an end thereof is outside the cage, said high voltage socket having a body of generally the same cross section, but of smaller area than said aperture and further having a pair of mounting lugs for afiixing said socket to said top; a vacuum tube mounted in said socket and extending into said cage; a burnable transformer mounted in said cage below said socket; a platform of non-flammable, non-meltable material mounted in said cage between said socket and said transformer, said platform underlying said socket in near supporting relationship thereto and including an aperture permitting said vacuum tube to extend therethrough; means, including an opening in said socket, permitting passage therethrough of interconnecting high voltage conductors between said socket and said transformer; both said apertures coopcrating to allow escape of warm air from said cage; said socket melting and, aided by the weight of said tube, sagging into said cage into supporting relationship with said platform and into sealing engagement with the aperture in said platform upon occurrence of abnormally high temperatures due to burning of said transformer; and a non-flammable insulating cap covering the end of said socket outside said cage and performing the functions of high voltage shock protection and sealing said openmg.

References Cited by the Examiner UNITED STATES PATENTS 2,022,644 12/35 Ashcraft 3l7l00 2,428,948 10/47 Torsch et al. 336-107 KATHLEEN H. CLAFFY, Primary Examiner.

JOHN F. BURNS, Examiner. 

1. IN A TELEVISION RECEIVER, A HIGH VOLTAGE CAGE HAVING AN APERTURE IN THE TOP WALL THEREOF; A BURNABLE TRANSFORMER IN SAID HIGH VOLTAGE CAGE; A TUBE SOCKET FABRICATED OF A MELTABLE, NON-FLAMMABLE MATERIAL MOUNTED IN SAID APERTURE; A PLATFORM OF NON-FLAMMABLE, NON-METABLE MATERIAL; AN APETURE IN SAID PLATFORM FOR ALLOWING AIR TO CIRCULATE THROGH SAID HIGH VOLTAGE CAGE; SAID PLATFORM MOUNTED IN SAID HIGH VOLTAGE CAGE IN A POSIITON INTERMEDIATE SAID TRANSFORMER AND SAID TUBE SOCKET SUCH THAT SAID TUBE SOCKET IN MELTING SAGS INTO SAID HIGH VOLTAGE CAGE AND SEALS SAID APERTURE IN SAID PLATFORM THEREBY PREVENTING SAID AIR FROM CIRCULATING IN SAID HIGH VOLTAGE CAGE, WHEREBY FIRE RESULTING FROM THEBURNING OF SAID TRNASFORMER IS RETARDED AND PREVENTED FROM ESCAPING FROM SAID HIGH VOLTAGE CAGE. 